Small tweak to remove a connection from a context when it is closed.
Small tweak to remove a connection from a context when it is closed.

* context.c:
  (GET_CONN): new macro to access a connection within a context
  (open_connections): use GET_CONN rather than manual indexing
  (serf_connection_close): use GET_CONN rather than manual indexing. after
    closing the bits in the connection, remove it from the context. have
    the function return APR_NOTFOUND if the connection is unknown.

zhengcq315/serf,stoneCC/serf,idomon/serf,KyleSanderson/serf,TommyU/serf,alex1818/serf,zhupan/serf,alex1818/serf,soufianeEL/serf,pengdu/serf,lazysoez/serf,soufianeEL/serf,alex1818/serf,liuzongquan/serf,idomon/serf,muthusuba/serf,zhupan/serf,justinweb/serf,KyleSanderson/serf,muthusuba/serf,muthusuba/serf,wzugang/serf,pengdu/serf,x-clone/serf,TommyU/serf,zhupan/serf,SirJson/serf,muthusuba/serf,TommyU/serf,pengdu/serf,Manouchehri/serf,pengdu/serf,SirJson/serf,lazysoez/serf,stoneCC/serf,lazysoez/serf,yesoce/serf,yesoce/serf,x-clone/serf,stoneCC/serf,google-code-export/serf,SirJson/serf,Manouchehri/serf,krime/serf,wzugang/serf,wzugang/serf,TommyU/serf,sworda/serf,idomon/serf,google-code-export/serf,zhengcq315/serf,x-clone/serf,SirJson/serf,zhengcq315/serf,krime/serf,sworda/serf,google-code-export/serf,wzugang/serf,justinweb/serf,alex1818/serf,lazysoez/serf,Manouchehri/serf,justinweb/serf,Manouchehri/serf,blueszhangsh/serf,justinweb/serf,yesoce/serf,idomon/serf,yesoce/serf,krime/serf,KyleSanderson/serf,stoneCC/serf,liuzongquan/serf,soufianeEL/serf,liuzongquan/serf,liuzongquan/serf,x-clone/serf,sworda/serf,blueszhangsh/serf,google-code-export/serf,zhengcq315/serf,blueszhangsh/serf,soufianeEL/serf,zhupan/serf,blueszhangsh/serf,sworda/serf,KyleSanderson/serf,krime/serf